Technical Field
The technology relates to driving circuitry for biasing radio-frequency components, such as PIN diodes and gallium-nitride devices.
Discussion of the Related Art
Semiconductor diodes with wide, intrinsic semiconductor regions between p-type and n-type semiconductor regions on either side of the diode junction are referred to as “PIN” diodes. PIN diodes can be used in radio-frequency (RF) applications as switches and/or attenuators, and may be used in other applications as photodetectors and photovoltaic cells. When a PIN diode is forward biased, the PIN diode becomes conductive and can readily pass an RF signal. Under forward bias, the PIN diode essentially appears as a short. When at zero bias or reverse bias, a PIN diode is mainly a capacitive element, since the intrinsic region of the diode is depleted of carriers, and may effectively block an RF signal. The capacitance of a PIN diode can be small (e.g., on the order of 1 pF or less). Because a PIN diode has small capacitance, it can be switched at high speed between conductive and capacitive states which makes it attractive for RF applications.
Gallium-nitride (GaN) amplifiers may include GaN transistors, such as high-electron mobility transistors (HEMTs), formed from gallium-nitride material. These amplifiers are useful for RF communications and radar applications because of their high-speed and high-breakdown-voltage capabilities. Gallium-nitride amplifiers may be biased with negative voltages as high as −20 volts in some cases (e.g., to prevent conduction) and also with high positive voltages.